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implied: create fake implication history
[smatch.git] / smatch_comparison.c
blobd4f9e4944ef10ce2f2dd817845aa4be1b28701da
1 /*
2 * Copyright (C) 2012 Oracle.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version 2
7 * of the License, or (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, see http://www.gnu.org/copyleft/gpl.txt
16 */
17
18 /*
19 * The point here is to store the relationships between two variables.
20 * Ie: y > x.
21 * To do that we create a state with the two variables in alphabetical order:
22 * ->name = "x vs y" and the state would be "<". On the false path the state
23 * would be ">=".
24 *
25 * Part of the trick of it is that if x or y is modified then we need to reset
26 * the state. We need to keep a list of all the states which depend on x and
27 * all the states which depend on y. The link_id code handles this.
28 *
29 */
30
31 #include "smatch.h"
32 #include "smatch_extra.h"
33 #include "smatch_slist.h"
34
35 static int compare_id;
36 static int link_id;
37 static int inc_dec_id;
38 static int inc_dec_link_id;
39
40 /* for handling for loops */
41 STATE(start);
42 STATE(incremented);
43
44 ALLOCATOR(compare_data, "compare data");
45
46 static struct symbol *vsl_to_sym(struct var_sym_list *vsl)
47 {
48 struct var_sym *vs;
49
50 if (!vsl)
51 return NULL;
52 if (ptr_list_size((struct ptr_list *)vsl) != 1)
53 return NULL;
54 vs = first_ptr_list((struct ptr_list *)vsl);
55 return vs->sym;
56 }
57
58 static struct smatch_state *alloc_compare_state(
59 const char *var1, struct var_sym_list *vsl1,
60 int comparison,
61 const char *var2, struct var_sym_list *vsl2)
62 {
63 struct smatch_state *state;
64 struct compare_data *data;
65
66 state = __alloc_smatch_state(0);
67 state->name = alloc_sname(show_special(comparison));
68 data = __alloc_compare_data(0);
69 data->var1 = alloc_sname(var1);
70 data->vsl1 = clone_var_sym_list(vsl1);
71 data->comparison = comparison;
72 data->var2 = alloc_sname(var2);
73 data->vsl2 = clone_var_sym_list(vsl2);
74 state->data = data;
75 return state;
76 }
77
78 static int state_to_comparison(struct smatch_state *state)
79 {
80 if (!state || !state->data)
81 return 0;
82 return ((struct compare_data *)state->data)->comparison;
83 }
84
85 /*
86 * flip_comparison() reverses the op left and right. So "x >= y" becomes "y <= x".
87 */
88 int flip_comparison(int op)
89 {
90 switch (op) {
91 case 0:
92 return 0;
93 case '<':
94 return '>';
95 case SPECIAL_UNSIGNED_LT:
96 return SPECIAL_UNSIGNED_GT;
97 case SPECIAL_LTE:
98 return SPECIAL_GTE;
99 case SPECIAL_UNSIGNED_LTE:
100 return SPECIAL_UNSIGNED_GTE;
101 case SPECIAL_EQUAL:
102 return SPECIAL_EQUAL;
103 case SPECIAL_NOTEQUAL:
104 return SPECIAL_NOTEQUAL;
105 case SPECIAL_GTE:
106 return SPECIAL_LTE;
107 case SPECIAL_UNSIGNED_GTE:
108 return SPECIAL_UNSIGNED_LTE;
109 case '>':
110 return '<';
111 case SPECIAL_UNSIGNED_GT:
112 return SPECIAL_UNSIGNED_LT;
113 default:
114 sm_msg("internal smatch bug. unhandled comparison %d", op);
115 return op;
116 }
117 }
118
119 int negate_comparison(int op)
120 {
121 switch (op) {
122 case 0:
123 return 0;
124 case '<':
125 return SPECIAL_GTE;
126 case SPECIAL_UNSIGNED_LT:
127 return SPECIAL_UNSIGNED_GTE;
128 case SPECIAL_LTE:
129 return '>';
130 case SPECIAL_UNSIGNED_LTE:
131 return SPECIAL_UNSIGNED_GT;
132 case SPECIAL_EQUAL:
133 return SPECIAL_NOTEQUAL;
134 case SPECIAL_NOTEQUAL:
135 return SPECIAL_EQUAL;
136 case SPECIAL_GTE:
137 return '<';
138 case SPECIAL_UNSIGNED_GTE:
139 return SPECIAL_UNSIGNED_LT;
140 case '>':
141 return SPECIAL_LTE;
142 case SPECIAL_UNSIGNED_GT:
143 return SPECIAL_UNSIGNED_LTE;
144 default:
145 sm_msg("internal smatch bug. unhandled comparison %d", op);
146 return op;
147 }
148 }
149
150 static int rl_comparison(struct range_list *left_rl, struct range_list *right_rl)
151 {
152 sval_t left_min, left_max, right_min, right_max;
153
154 if (!left_rl || !right_rl)
155 return 0;
156
157 left_min = rl_min(left_rl);
158 left_max = rl_max(left_rl);
159 right_min = rl_min(right_rl);
160 right_max = rl_max(right_rl);
161
162 if (left_min.value == left_max.value &&
163 right_min.value == right_max.value &&
164 left_min.value == right_min.value)
165 return SPECIAL_EQUAL;
166
167 if (sval_cmp(left_max, right_min) < 0)
168 return '<';
169 if (sval_cmp(left_max, right_min) == 0)
170 return SPECIAL_LTE;
171 if (sval_cmp(left_min, right_max) > 0)
172 return '>';
173 if (sval_cmp(left_min, right_max) == 0)
174 return SPECIAL_GTE;
175
176 return 0;
177 }
178
179 static struct range_list *get_orig_rl(struct var_sym_list *vsl)
180 {
181 struct symbol *sym;
182 struct smatch_state *state;
183
184 if (!vsl)
185 return NULL;
186 sym = vsl_to_sym(vsl);
187 if (!sym || !sym->ident)
188 return NULL;
189 state = get_orig_estate(sym->ident->name, sym);
190 return estate_rl(state);
191 }
192
193 static struct smatch_state *unmatched_comparison(struct sm_state *sm)
194 {
195 struct compare_data *data = sm->state->data;
196 struct range_list *left_rl, *right_rl;
197 int op;
198
199 if (!data)
200 return &undefined;
201
202 if (strstr(data->var1, " orig"))
203 left_rl = get_orig_rl(data->vsl1);
204 else if (!get_implied_rl_var_sym(data->var1, vsl_to_sym(data->vsl1), &left_rl))
205 return &undefined;
206 if (strstr(data->var2, " orig"))
207 right_rl = get_orig_rl(data->vsl2);
208 else if (!get_implied_rl_var_sym(data->var2, vsl_to_sym(data->vsl2), &right_rl))
209 return &undefined;
210
211
212 op = rl_comparison(left_rl, right_rl);
213 if (op)
214 return alloc_compare_state(data->var1, data->vsl1, op, data->var2, data->vsl2);
215
216 return &undefined;
217 }
218
219 /* remove_unsigned_from_comparison() is obviously a hack. */
220 static int remove_unsigned_from_comparison(int op)
221 {
222 switch (op) {
223 case SPECIAL_UNSIGNED_LT:
224 return '<';
225 case SPECIAL_UNSIGNED_LTE:
226 return SPECIAL_LTE;
227 case SPECIAL_UNSIGNED_GTE:
228 return SPECIAL_GTE;
229 case SPECIAL_UNSIGNED_GT:
230 return '>';
231 default:
232 return op;
233 }
234 }
235
236 /*
237 * This is for when you merge states "a < b" and "a == b", the result is that
238 * we can say for sure, "a <= b" after the merge.
239 */
240 static int merge_comparisons(int one, int two)
241 {
242 int LT, EQ, GT;
243
244 one = remove_unsigned_from_comparison(one);
245 two = remove_unsigned_from_comparison(two);
246
247 if (one == two)
248 return one;
249
250 LT = EQ = GT = 0;
251
252 switch (one) {
253 case '<':
254 LT = 1;
255 break;
256 case SPECIAL_LTE:
257 LT = 1;
258 EQ = 1;
259 break;
260 case SPECIAL_EQUAL:
261 EQ = 1;
262 break;
263 case SPECIAL_GTE:
264 GT = 1;
265 EQ = 1;
266 break;
267 case '>':
268 GT = 1;
269 }
270
271 switch (two) {
272 case '<':
273 LT = 1;
274 break;
275 case SPECIAL_LTE:
276 LT = 1;
277 EQ = 1;
278 break;
279 case SPECIAL_EQUAL:
280 EQ = 1;
281 break;
282 case SPECIAL_GTE:
283 GT = 1;
284 EQ = 1;
285 break;
286 case '>':
287 GT = 1;
288 }
289
290 if (LT && EQ && GT)
291 return 0;
292 if (LT && EQ)
293 return SPECIAL_LTE;
294 if (LT && GT)
295 return SPECIAL_NOTEQUAL;
296 if (LT)
297 return '<';
298 if (EQ && GT)
299 return SPECIAL_GTE;
300 if (GT)
301 return '>';
302 return 0;
303 }
304
305 /*
306 * This is for if you have "a < b" and "b <= c". Or in other words,
307 * "a < b <= c". You would call this like get_combined_comparison('<', '<=').
308 * The return comparison would be '<'.
309 *
310 * This function is different from merge_comparisons(), for example:
311 * merge_comparison('<', '==') returns '<='
312 * get_combined_comparison('<', '==') returns '<'
313 */
314 static int combine_comparisons(int left_compare, int right_compare)
315 {
316 int LT, EQ, GT;
317
318 left_compare = remove_unsigned_from_comparison(left_compare);
319 right_compare = remove_unsigned_from_comparison(right_compare);
320
321 LT = EQ = GT = 0;
322
323 switch (left_compare) {
324 case '<':
325 LT++;
326 break;
327 case SPECIAL_LTE:
328 LT++;
329 EQ++;
330 break;
331 case SPECIAL_EQUAL:
332 return right_compare;
333 case SPECIAL_GTE:
334 GT++;
335 EQ++;
336 break;
337 case '>':
338 GT++;
339 }
340
341 switch (right_compare) {
342 case '<':
343 LT++;
344 break;
345 case SPECIAL_LTE:
346 LT++;
347 EQ++;
348 break;
349 case SPECIAL_EQUAL:
350 return left_compare;
351 case SPECIAL_GTE:
352 GT++;
353 EQ++;
354 break;
355 case '>':
356 GT++;
357 }
358
359 if (LT == 2) {
360 if (EQ == 2)
361 return SPECIAL_LTE;
362 return '<';
363 }
364
365 if (GT == 2) {
366 if (EQ == 2)
367 return SPECIAL_GTE;
368 return '>';
369 }
370 return 0;
371 }
372
373 static int filter_comparison(int orig, int op)
374 {
375 if (orig == op)
376 return orig;
377
378 switch (orig) {
379 case 0:
380 return op;
381 case '<':
382 switch (op) {
383 case '<':
384 case SPECIAL_LTE:
385 case SPECIAL_NOTEQUAL:
386 return '<';
387 }
388 return 0;
389 case SPECIAL_LTE:
390 switch (op) {
391 case '<':
392 case SPECIAL_LTE:
393 case SPECIAL_EQUAL:
394 return op;
395 case SPECIAL_NOTEQUAL:
396 return '<';
397 }
398 return 0;
399 case SPECIAL_EQUAL:
400 switch (op) {
401 case SPECIAL_LTE:
402 case SPECIAL_EQUAL:
403 case SPECIAL_GTE:
404 case SPECIAL_UNSIGNED_LTE:
405 case SPECIAL_UNSIGNED_GTE:
406 return SPECIAL_EQUAL;
407 }
408 return 0;
409 case SPECIAL_NOTEQUAL:
410 switch (op) {
411 case '<':
412 case SPECIAL_LTE:
413 return '<';
414 case SPECIAL_UNSIGNED_LT:
415 case SPECIAL_UNSIGNED_LTE:
416 return SPECIAL_UNSIGNED_LT;
417 case SPECIAL_NOTEQUAL:
418 return op;
419 case '>':
420 case SPECIAL_GTE:
421 return '>';
422 case SPECIAL_UNSIGNED_GT:
423 case SPECIAL_UNSIGNED_GTE:
424 return SPECIAL_UNSIGNED_GT;
425 }
426 return 0;
427 case SPECIAL_GTE:
428 switch (op) {
429 case SPECIAL_LTE:
430 return SPECIAL_EQUAL;
431 case '>':
432 case SPECIAL_GTE:
433 case SPECIAL_EQUAL:
434 return op;
435 case SPECIAL_NOTEQUAL:
436 return '>';
437 }
438 return 0;
439 case '>':
440 switch (op) {
441 case '>':
442 case SPECIAL_GTE:
443 case SPECIAL_NOTEQUAL:
444 return '>';
445 }
446 return 0;
447 case SPECIAL_UNSIGNED_LT:
448 switch (op) {
449 case SPECIAL_UNSIGNED_LT:
450 case SPECIAL_UNSIGNED_LTE:
451 case SPECIAL_NOTEQUAL:
452 return SPECIAL_UNSIGNED_LT;
453 }
454 return 0;
455 case SPECIAL_UNSIGNED_LTE:
456 switch (op) {
457 case SPECIAL_UNSIGNED_LT:
458 case SPECIAL_UNSIGNED_LTE:
459 case SPECIAL_EQUAL:
460 return op;
461 case SPECIAL_NOTEQUAL:
462 return SPECIAL_UNSIGNED_LT;
463 case SPECIAL_UNSIGNED_GTE:
464 return SPECIAL_EQUAL;
465 }
466 return 0;
467 case SPECIAL_UNSIGNED_GTE:
468 switch (op) {
469 case SPECIAL_UNSIGNED_LTE:
470 return SPECIAL_EQUAL;
471 case SPECIAL_NOTEQUAL:
472 return SPECIAL_UNSIGNED_GT;
473 case SPECIAL_EQUAL:
474 case SPECIAL_UNSIGNED_GTE:
475 case SPECIAL_UNSIGNED_GT:
476 return op;
477 }
478 return 0;
479 case SPECIAL_UNSIGNED_GT:
480 switch (op) {
481 case SPECIAL_UNSIGNED_GT:
482 case SPECIAL_UNSIGNED_GTE:
483 case SPECIAL_NOTEQUAL:
484 return SPECIAL_UNSIGNED_GT;
485 }
486 return 0;
487 }
488 return 0;
489 }
490
491 static struct smatch_state *merge_compare_states(struct smatch_state *s1, struct smatch_state *s2)
492 {
493 struct compare_data *data = s1->data;
494 int op;
495
496 op = merge_comparisons(state_to_comparison(s1), state_to_comparison(s2));
497 if (op)
498 return alloc_compare_state(data->var1, data->vsl1, op, data->var2, data->vsl2);
499 return &undefined;
500 }
501
502 static struct smatch_state *alloc_link_state(struct string_list *links)
503 {
504 struct smatch_state *state;
505 static char buf[256];
506 char *tmp;
507 int i;
508
509 state = __alloc_smatch_state(0);
510
511 i = 0;
512 FOR_EACH_PTR(links, tmp) {
513 if (!i++) {
514 snprintf(buf, sizeof(buf), "%s", tmp);
515 } else {
516 append(buf, ", ", sizeof(buf));
517 append(buf, tmp, sizeof(buf));
518 }
519 } END_FOR_EACH_PTR(tmp);
520
521 state->name = alloc_sname(buf);
522 state->data = links;
523 return state;
524 }
525
526 static void save_start_states(struct statement *stmt)
527 {
528 struct symbol *param;
529 char orig[64];
530 char state_name[128];
531 struct smatch_state *state;
532 struct string_list *links;
533 char *link;
534
535 FOR_EACH_PTR(cur_func_sym->ctype.base_type->arguments, param) {
536 struct var_sym_list *vsl1 = NULL;
537 struct var_sym_list *vsl2 = NULL;
538
539 if (!param->ident)
540 continue;
541 snprintf(orig, sizeof(orig), "%s orig", param->ident->name);
542 snprintf(state_name, sizeof(state_name), "%s vs %s", param->ident->name, orig);
543 add_var_sym(&vsl1, param->ident->name, param);
544 add_var_sym(&vsl2, orig, param);
545 state = alloc_compare_state(param->ident->name, vsl1, SPECIAL_EQUAL, alloc_sname(orig), vsl2);
546 set_state(compare_id, state_name, NULL, state);
547
548 link = alloc_sname(state_name);
549 links = NULL;
550 insert_string(&links, link);
551 state = alloc_link_state(links);
552 set_state(link_id, param->ident->name, param, state);
553 } END_FOR_EACH_PTR(param);
554 }
555
556 static struct smatch_state *merge_links(struct smatch_state *s1, struct smatch_state *s2)
557 {
558 struct smatch_state *ret;
559 struct string_list *links;
560
561 links = combine_string_lists(s1->data, s2->data);
562 ret = alloc_link_state(links);
563 return ret;
564 }
565
566 static void save_link_var_sym(const char *var, struct symbol *sym, const char *link)
567 {
568 struct smatch_state *old_state, *new_state;
569 struct string_list *links;
570 char *new;
571
572 old_state = get_state(link_id, var, sym);
573 if (old_state)
574 links = clone_str_list(old_state->data);
575 else
576 links = NULL;
577
578 new = alloc_sname(link);
579 insert_string(&links, new);
580
581 new_state = alloc_link_state(links);
582 set_state(link_id, var, sym, new_state);
583 }
584
585 static void match_inc(struct sm_state *sm)
586 {
587 struct string_list *links;
588 struct smatch_state *state;
589 char *tmp;
590
591 links = sm->state->data;
592
593 FOR_EACH_PTR(links, tmp) {
594 state = get_state(compare_id, tmp, NULL);
595
596 switch (state_to_comparison(state)) {
597 case SPECIAL_EQUAL:
598 case SPECIAL_GTE:
599 case SPECIAL_UNSIGNED_GTE:
600 case '>':
601 case SPECIAL_UNSIGNED_GT: {
602 struct compare_data *data = state->data;
603 struct smatch_state *new;
604
605 new = alloc_compare_state(data->var1, data->vsl1, '>', data->var2, data->vsl2);
606 set_state(compare_id, tmp, NULL, new);
607 break;
608 }
609 default:
610 set_state(compare_id, tmp, NULL, &undefined);
611 }
612 } END_FOR_EACH_PTR(tmp);
613 }
614
615 static void match_dec(struct sm_state *sm)
616 {
617 struct string_list *links;
618 struct smatch_state *state;
619 char *tmp;
620
621 links = sm->state->data;
622
623 FOR_EACH_PTR(links, tmp) {
624 state = get_state(compare_id, tmp, NULL);
625
626 switch (state_to_comparison(state)) {
627 case SPECIAL_EQUAL:
628 case SPECIAL_LTE:
629 case SPECIAL_UNSIGNED_LTE:
630 case '<':
631 case SPECIAL_UNSIGNED_LT: {
632 struct compare_data *data = state->data;
633 struct smatch_state *new;
634
635 new = alloc_compare_state(data->var1, data->vsl1, '<', data->var2, data->vsl2);
636 set_state(compare_id, tmp, NULL, new);
637 break;
638 }
639 default:
640 set_state(compare_id, tmp, NULL, &undefined);
641 }
642 } END_FOR_EACH_PTR(tmp);
643 }
644
645 static int match_inc_dec(struct sm_state *sm, struct expression *mod_expr)
646 {
647 if (!mod_expr)
648 return 0;
649 if (mod_expr->type != EXPR_PREOP && mod_expr->type != EXPR_POSTOP)
650 return 0;
651
652 if (mod_expr->op == SPECIAL_INCREMENT) {
653 match_inc(sm);
654 return 1;
655 }
656 if (mod_expr->op == SPECIAL_DECREMENT) {
657 match_dec(sm);
658 return 1;
659 }
660 return 0;
661 }
662
663 static void match_modify(struct sm_state *sm, struct expression *mod_expr)
664 {
665 struct string_list *links;
666 char *tmp;
667
668 /*
669 * if (foo > bar) then ++foo is also > bar.
670 */
671 if (match_inc_dec(sm, mod_expr))
672 return;
673
674 links = sm->state->data;
675
676 FOR_EACH_PTR(links, tmp) {
677 set_state(compare_id, tmp, NULL, &undefined);
678 } END_FOR_EACH_PTR(tmp);
679 set_state(link_id, sm->name, sm->sym, &undefined);
680 }
681
682 static char *chunk_to_var_sym(struct expression *expr, struct symbol **sym)
683 {
684 expr = strip_expr(expr);
685 if (!expr)
686 return NULL;
687 if (sym)
688 *sym = NULL;
689
690 if (expr->type == EXPR_PREOP &&
691 (expr->op == SPECIAL_INCREMENT ||
692 expr->op == SPECIAL_DECREMENT))
693 expr = strip_expr(expr->unop);
694
695 return expr_to_chunk_sym_vsl(expr, sym, NULL);
696 }
697
698 static char *chunk_to_var(struct expression *expr)
699 {
700 return chunk_to_var_sym(expr, NULL);
701 }
702
703 static void save_link(struct expression *expr, char *link)
704 {
705 char *var;
706 struct symbol *sym;
707
708 expr = strip_expr(expr);
709 if (expr->type == EXPR_BINOP) {
710 char *chunk;
711
712 chunk = chunk_to_var(expr);
713 if (!chunk)
714 return;
715
716 save_link(expr->left, link);
717 save_link(expr->right, link);
718 save_link_var_sym(chunk, NULL, link);
719 return;
720 }
721
722 var = expr_to_var_sym(expr, &sym);
723 if (!var || !sym)
724 goto done;
725
726 save_link_var_sym(var, sym, link);
727 done:
728 free_string(var);
729 }
730
731 static int get_orig_comparison(struct stree *pre_stree, const char *left, const char *right)
732 {
733 struct smatch_state *state;
734 struct compare_data *data;
735 int flip = 0;
736 char state_name[256];
737
738 if (strcmp(left, right) > 0) {
739 const char *tmp = right;
740
741 flip = 1;
742 right = left;
743 left = tmp;
744 }
745
746 snprintf(state_name, sizeof(state_name), "%s vs %s", left, right);
747 state = get_state_stree(pre_stree, compare_id, state_name, NULL);
748 if (!state || !state->data)
749 return 0;
750 data = state->data;
751 if (flip)
752 return flip_comparison(data->comparison);
753 return data->comparison;
754
755 }
756
757 static int have_common_var_sym(struct var_sym_list *left_vsl, struct var_sym_list *right_vsl)
758 {
759 struct var_sym *tmp;
760
761 FOR_EACH_PTR(left_vsl, tmp) {
762 if (in_var_sym_list(right_vsl, tmp->var, tmp->sym))
763 return 1;
764 } END_FOR_EACH_PTR(tmp);
765
766 return 0;
767 }
768
769 /*
770 * The idea here is that we take a comparison "a < b" and then we look at all
771 * the things which "b" is compared against "b < c" and we say that that implies
772 * a relationship "a < c".
773 *
774 * The names here about because the comparisons are organized like this
775 * "a < b < c".
776 *
777 */
778 static void update_tf_links(struct stree *pre_stree,
779 const char *left_var, struct var_sym_list *left_vsl,
780 int left_comparison, int left_false_comparison,
781 const char *mid_var, struct var_sym_list *mid_vsl,
782 struct string_list *links)
783 {
784 struct smatch_state *state;
785 struct smatch_state *true_state, *false_state;
786 struct compare_data *data;
787 const char *right_var;
788 struct var_sym_list *right_vsl;
789 int orig_comparison;
790 int right_comparison;
791 int true_comparison;
792 int false_comparison;
793 char *tmp;
794 char state_name[256];
795 struct var_sym *vs;
796
797 FOR_EACH_PTR(links, tmp) {
798 state = get_state_stree(pre_stree, compare_id, tmp, NULL);
799 if (!state || !state->data)
800 continue;
801 data = state->data;
802 right_comparison = data->comparison;
803 right_var = data->var2;
804 right_vsl = data->vsl2;
805 if (strcmp(mid_var, right_var) == 0) {
806 right_var = data->var1;
807 right_vsl = data->vsl1;
808 right_comparison = flip_comparison(right_comparison);
809 }
810 if (have_common_var_sym(left_vsl, right_vsl))
811 continue;
812
813 orig_comparison = get_orig_comparison(pre_stree, left_var, right_var);
814
815 true_comparison = combine_comparisons(left_comparison, right_comparison);
816 false_comparison = combine_comparisons(left_false_comparison, right_comparison);
817
818 true_comparison = filter_comparison(orig_comparison, true_comparison);
819 false_comparison = filter_comparison(orig_comparison, false_comparison);
820
821 if (strcmp(left_var, right_var) > 0) {
822 const char *tmp_var = left_var;
823 struct var_sym_list *tmp_vsl = left_vsl;
824
825 left_var = right_var;
826 left_vsl = right_vsl;
827 right_var = tmp_var;
828 right_vsl = tmp_vsl;
829 true_comparison = flip_comparison(true_comparison);
830 false_comparison = flip_comparison(false_comparison);
831 }
832
833 if (!true_comparison && !false_comparison)
834 continue;
835
836 if (true_comparison)
837 true_state = alloc_compare_state(left_var, left_vsl, true_comparison, right_var, right_vsl);
838 else
839 true_state = NULL;
840 if (false_comparison)
841 false_state = alloc_compare_state(left_var, left_vsl, false_comparison, right_var, right_vsl);
842 else
843 false_state = NULL;
844
845 snprintf(state_name, sizeof(state_name), "%s vs %s", left_var, right_var);
846 set_true_false_states(compare_id, state_name, NULL, true_state, false_state);
847 FOR_EACH_PTR(left_vsl, vs) {
848 save_link_var_sym(vs->var, vs->sym, state_name);
849 } END_FOR_EACH_PTR(vs);
850 FOR_EACH_PTR(right_vsl, vs) {
851 save_link_var_sym(vs->var, vs->sym, state_name);
852 } END_FOR_EACH_PTR(vs);
853 if (!vsl_to_sym(left_vsl))
854 save_link_var_sym(left_var, NULL, state_name);
855 if (!vsl_to_sym(right_vsl))
856 save_link_var_sym(right_var, NULL, state_name);
857 } END_FOR_EACH_PTR(tmp);
858 }
859
860 static void update_tf_data(struct stree *pre_stree,
861 const char *left_name, struct var_sym_list *left_vsl,
862 const char *right_name, struct var_sym_list *right_vsl,
863 int true_comparison, int false_comparison)
864 {
865 struct smatch_state *state;
866
867 state = get_state_stree(pre_stree, link_id, right_name, vsl_to_sym(right_vsl));
868 if (state)
869 update_tf_links(pre_stree, left_name, left_vsl, true_comparison, false_comparison, right_name, right_vsl, state->data);
870
871 state = get_state_stree(pre_stree, link_id, left_name, vsl_to_sym(left_vsl));
872 if (state)
873 update_tf_links(pre_stree, right_name, right_vsl, flip_comparison(true_comparison), flip_comparison(false_comparison), left_name, left_vsl, state->data);
874 }
875
876 static void iter_modify(struct sm_state *sm, struct expression *mod_expr)
877 {
878 if (sm->state != &start ||
879 !mod_expr ||
880 (mod_expr->type != EXPR_PREOP && mod_expr->type != EXPR_POSTOP) ||
881 mod_expr->op != SPECIAL_INCREMENT)
882 set_state(inc_dec_id, sm->name, sm->sym, &undefined);
883 else
884 set_state(inc_dec_id, sm->name, sm->sym, &incremented);
885 }
886
887 static void handle_for_loops(struct expression *expr, char *state_name, struct smatch_state *false_state)
888 {
889 sval_t sval;
890 char *iter_name, *cap_name;
891 struct symbol *iter_sym, *cap_sym;
892 struct compare_data *data;
893
894 if (expr->op != '<' && expr->op != SPECIAL_UNSIGNED_LT)
895 return;
896
897 if (!__cur_stmt || !__prev_stmt)
898 return;
899 if (__cur_stmt->type != STMT_ITERATOR)
900 return;
901 if (__cur_stmt->iterator_pre_condition != expr)
902 return;
903
904 /* literals are handled in smatch_extra.c */
905 if (get_value(expr->right, &sval))
906 return;
907
908 /* First time checking the condition */
909 if (__prev_stmt == __cur_stmt->iterator_pre_statement) {
910 if (!get_implied_value(expr->left, &sval) ||
911 sval.value != 0)
912 return;
913
914 iter_name = expr_to_var_sym(expr->left, &iter_sym);
915 cap_name = expr_to_var_sym(expr->right, &cap_sym);
916 if (!iter_name || !cap_name || !iter_sym || !cap_sym) {
917 free_string(iter_name);
918 free_string(cap_name);
919 return;
920 }
921
922 set_state(inc_dec_id, iter_name, iter_sym, &start);
923 store_link(inc_dec_link_id, cap_name, cap_sym, iter_name, iter_sym);
924
925 free_string(iter_name);
926 free_string(cap_name);
927 return;
928 }
929
930 /* Second time checking the condtion */
931 if (__prev_stmt != __cur_stmt->iterator_post_statement)
932 return;
933
934 if (get_state_expr(inc_dec_id, expr->left) != &incremented)
935 return;
936
937 data = false_state->data;
938 false_state = alloc_compare_state(data->var1, data->vsl1, SPECIAL_EQUAL, data->var2, data->vsl2);
939
940 set_true_false_states(compare_id, state_name, NULL, NULL, false_state);
941 }
942
943 static void handle_comparison(struct expression *expr_left, int op, struct expression *expr_right, char **_state_name, struct smatch_state **_false_state)
944 {
945 char *left = NULL;
946 char *right = NULL;
947 struct symbol *left_sym, *right_sym;
948 struct var_sym_list *left_vsl, *right_vsl;
949 int false_op;
950 int orig_comparison;
951 struct smatch_state *true_state, *false_state;
952 static char state_name[256];
953 struct stree *pre_stree;
954 sval_t sval;
955
956 false_op = negate_comparison(op);
957
958 if (op == SPECIAL_UNSIGNED_LT &&
959 get_implied_value(expr_left, &sval) &&
960 sval.value == 0)
961 false_op = SPECIAL_EQUAL;
962
963 if (op == SPECIAL_UNSIGNED_GT &&
964 get_implied_value(expr_right, &sval) &&
965 sval.value == 0)
966 false_op = SPECIAL_EQUAL;
967
968 left = chunk_to_var_sym(expr_left, &left_sym);
969 if (!left)
970 goto free;
971 left_vsl = expr_to_vsl(expr_left);
972 right = chunk_to_var_sym(expr_right, &right_sym);
973 if (!right)
974 goto free;
975 right_vsl = expr_to_vsl(expr_right);
976
977 if (strcmp(left, right) > 0) {
978 struct symbol *tmp_sym = left_sym;
979 char *tmp_name = left;
980 struct var_sym_list *tmp_vsl = left_vsl;
981
982 left = right;
983 left_sym = right_sym;
984 left_vsl = right_vsl;
985 right = tmp_name;
986 right_sym = tmp_sym;
987 right_vsl = tmp_vsl;
988 op = flip_comparison(op);
989 false_op = flip_comparison(false_op);
990 }
991
992 orig_comparison = get_comparison_strings(left, right);
993 op = filter_comparison(orig_comparison, op);
994 false_op = filter_comparison(orig_comparison, false_op);
995
996 snprintf(state_name, sizeof(state_name), "%s vs %s", left, right);
997 true_state = alloc_compare_state(left, left_vsl, op, right, right_vsl);
998 false_state = alloc_compare_state(left, left_vsl, false_op, right, right_vsl);
999
1000 pre_stree = clone_stree(__get_cur_stree());
1001 update_tf_data(pre_stree, left, left_vsl, right, right_vsl, op, false_op);
1002 free_stree(&pre_stree);
1003
1004 set_true_false_states(compare_id, state_name, NULL, true_state, false_state);
1005 save_link(expr_left, state_name);
1006 save_link(expr_right, state_name);
1007
1008 if (_false_state)
1009 *_false_state = false_state;
1010 if (_state_name)
1011 *_state_name = state_name;
1012 free:
1013 free_string(left);
1014 free_string(right);
1015
1016 }
1017
1018 void __comparison_match_condition(struct expression *expr)
1019 {
1020 struct expression *left, *right, *new_left, *new_right;
1021 struct smatch_state *false_state = NULL;
1022 char *state_name = NULL;
1023
1024 if (expr->type != EXPR_COMPARE)
1025 return;
1026
1027 handle_comparison(expr->left, expr->op, expr->right, &state_name, &false_state);
1028 if (false_state && state_name)
1029 handle_for_loops(expr, state_name, false_state);
1030
1031
1032 left = strip_parens(expr->left);
1033 right = strip_parens(expr->right);
1034
1035 if (left->type == EXPR_BINOP && left->op == '+') {
1036 new_left = left->left;
1037 new_right = binop_expression(right, '-', left->right);
1038 handle_comparison(new_left, expr->op, new_right, NULL, NULL);
1039
1040 new_left = left->right;
1041 new_right = binop_expression(right, '-', left->left);
1042 handle_comparison(new_left, expr->op, new_right, NULL, NULL);
1043 }
1044 }
1045
1046 static void add_comparison_var_sym(const char *left_name,
1047 struct var_sym_list *left_vsl,
1048 int comparison,
1049 const char *right_name, struct var_sym_list *right_vsl)
1050 {
1051 struct smatch_state *state;
1052 struct var_sym *vs;
1053 char state_name[256];
1054
1055 if (strcmp(left_name, right_name) > 0) {
1056 const char *tmp_name = left_name;
1057 struct var_sym_list *tmp_vsl = left_vsl;
1058
1059 left_name = right_name;
1060 left_vsl = right_vsl;
1061 right_name = tmp_name;
1062 right_vsl = tmp_vsl;
1063 comparison = flip_comparison(comparison);
1064 }
1065 snprintf(state_name, sizeof(state_name), "%s vs %s", left_name, right_name);
1066 state = alloc_compare_state(left_name, left_vsl, comparison, right_name, right_vsl);
1067
1068 set_state(compare_id, state_name, NULL, state);
1069
1070 FOR_EACH_PTR(left_vsl, vs) {
1071 save_link_var_sym(vs->var, vs->sym, state_name);
1072 } END_FOR_EACH_PTR(vs);
1073 FOR_EACH_PTR(right_vsl, vs) {
1074 save_link_var_sym(vs->var, vs->sym, state_name);
1075 } END_FOR_EACH_PTR(vs);
1076 }
1077
1078 static void add_comparison(struct expression *left, int comparison, struct expression *right)
1079 {
1080 char *left_name = NULL;
1081 char *right_name = NULL;
1082 struct symbol *left_sym, *right_sym;
1083 struct var_sym_list *left_vsl, *right_vsl;
1084 struct smatch_state *state;
1085 char state_name[256];
1086
1087 left_name = chunk_to_var_sym(left, &left_sym);
1088 if (!left_name)
1089 goto free;
1090 left_vsl = expr_to_vsl(left);
1091 right_name = chunk_to_var_sym(right, &right_sym);
1092 if (!right_name)
1093 goto free;
1094 right_vsl = expr_to_vsl(right);
1095
1096 if (strcmp(left_name, right_name) > 0) {
1097 struct symbol *tmp_sym = left_sym;
1098 char *tmp_name = left_name;
1099 struct var_sym_list *tmp_vsl = left_vsl;
1100
1101 left_name = right_name;
1102 left_sym = right_sym;
1103 left_vsl = right_vsl;
1104 right_name = tmp_name;
1105 right_sym = tmp_sym;
1106 right_vsl = tmp_vsl;
1107 comparison = flip_comparison(comparison);
1108 }
1109 snprintf(state_name, sizeof(state_name), "%s vs %s", left_name, right_name);
1110 state = alloc_compare_state(left_name, left_vsl, comparison, right_name, right_vsl);
1111
1112 set_state(compare_id, state_name, NULL, state);
1113 save_link(left, state_name);
1114 save_link(right, state_name);
1115
1116 free:
1117 free_string(left_name);
1118 free_string(right_name);
1119 }
1120
1121 static void match_assign_add(struct expression *expr)
1122 {
1123 struct expression *right;
1124 struct expression *r_left, *r_right;
1125 sval_t left_tmp, right_tmp;
1126
1127 right = strip_expr(expr->right);
1128 r_left = strip_expr(right->left);
1129 r_right = strip_expr(right->right);
1130
1131 get_absolute_min(r_left, &left_tmp);
1132 get_absolute_min(r_right, &right_tmp);
1133
1134 if (left_tmp.value > 0)
1135 add_comparison(expr->left, '>', r_right);
1136 else if (left_tmp.value == 0)
1137 add_comparison(expr->left, SPECIAL_GTE, r_right);
1138
1139 if (right_tmp.value > 0)
1140 add_comparison(expr->left, '>', r_left);
1141 else if (right_tmp.value == 0)
1142 add_comparison(expr->left, SPECIAL_GTE, r_left);
1143 }
1144
1145 static void match_assign_sub(struct expression *expr)
1146 {
1147 struct expression *right;
1148 struct expression *r_left, *r_right;
1149 int comparison;
1150 sval_t min;
1151
1152 right = strip_expr(expr->right);
1153 r_left = strip_expr(right->left);
1154 r_right = strip_expr(right->right);
1155
1156 if (get_absolute_min(r_right, &min) && sval_is_negative(min))
1157 return;
1158
1159 comparison = get_comparison(r_left, r_right);
1160
1161 switch (comparison) {
1162 case '>':
1163 case SPECIAL_GTE:
1164 if (implied_not_equal(r_right, 0))
1165 add_comparison(expr->left, '>', r_left);
1166 else
1167 add_comparison(expr->left, SPECIAL_GTE, r_left);
1168 return;
1169 }
1170 }
1171
1172 static void match_assign_divide(struct expression *expr)
1173 {
1174 struct expression *right;
1175 struct expression *r_left, *r_right;
1176 sval_t min;
1177
1178 right = strip_expr(expr->right);
1179 r_left = strip_expr(right->left);
1180 r_right = strip_expr(right->right);
1181 if (!get_implied_min(r_right, &min) || min.value <= 1)
1182 return;
1183
1184 add_comparison(expr->left, '<', r_left);
1185 }
1186
1187 static void match_binop_assign(struct expression *expr)
1188 {
1189 struct expression *right;
1190
1191 right = strip_expr(expr->right);
1192 if (right->op == '+')
1193 match_assign_add(expr);
1194 if (right->op == '-')
1195 match_assign_sub(expr);
1196 if (right->op == '/')
1197 match_assign_divide(expr);
1198 }
1199
1200 static void copy_comparisons(struct expression *left, struct expression *right)
1201 {
1202 struct string_list *links;
1203 struct smatch_state *state;
1204 struct compare_data *data;
1205 struct symbol *left_sym, *right_sym;
1206 char *left_var = NULL;
1207 char *right_var = NULL;
1208 struct var_sym_list *left_vsl;
1209 const char *var;
1210 struct var_sym_list *vsl;
1211 int comparison;
1212 char *tmp;
1213
1214 left_var = chunk_to_var_sym(left, &left_sym);
1215 if (!left_var)
1216 goto done;
1217 left_vsl = expr_to_vsl(left);
1218 right_var = chunk_to_var_sym(right, &right_sym);
1219 if (!right_var)
1220 goto done;
1221
1222 state = get_state(link_id, right_var, right_sym);
1223 if (!state)
1224 return;
1225 links = state->data;
1226
1227 FOR_EACH_PTR(links, tmp) {
1228 state = get_state(compare_id, tmp, NULL);
1229 if (!state || !state->data)
1230 continue;
1231 data = state->data;
1232 comparison = data->comparison;
1233 var = data->var2;
1234 vsl = data->vsl2;
1235 if (strcmp(var, right_var) == 0) {
1236 var = data->var1;
1237 vsl = data->vsl1;
1238 comparison = flip_comparison(comparison);
1239 }
1240 add_comparison_var_sym(left_var, left_vsl, comparison, var, vsl);
1241 } END_FOR_EACH_PTR(tmp);
1242
1243 done:
1244 free_string(right_var);
1245 }
1246
1247 static void match_assign(struct expression *expr)
1248 {
1249 struct expression *right;
1250
1251 if (expr->op != '=')
1252 return;
1253 if (__in_fake_assign || outside_of_function())
1254 return;
1255
1256 if (is_struct(expr->left))
1257 return;
1258
1259 copy_comparisons(expr->left, expr->right);
1260 add_comparison(expr->left, SPECIAL_EQUAL, expr->right);
1261
1262 right = strip_expr(expr->right);
1263 if (right->type == EXPR_BINOP)
1264 match_binop_assign(expr);
1265 }
1266
1267 int get_comparison_strings(const char *one, const char *two)
1268 {
1269 char buf[256];
1270 struct smatch_state *state;
1271 int invert = 0;
1272 int ret = 0;
1273
1274 if (strcmp(one, two) == 0)
1275 return SPECIAL_EQUAL;
1276
1277 if (strcmp(one, two) > 0) {
1278 const char *tmp = one;
1279
1280 one = two;
1281 two = tmp;
1282 invert = 1;
1283 }
1284
1285 snprintf(buf, sizeof(buf), "%s vs %s", one, two);
1286 state = get_state(compare_id, buf, NULL);
1287 if (state)
1288 ret = state_to_comparison(state);
1289
1290 if (invert)
1291 ret = flip_comparison(ret);
1292
1293 return ret;
1294 }
1295
1296 int get_comparison(struct expression *a, struct expression *b)
1297 {
1298 char *one = NULL;
1299 char *two = NULL;
1300 int ret = 0;
1301
1302 one = chunk_to_var(a);
1303 if (!one)
1304 goto free;
1305 two = chunk_to_var(b);
1306 if (!two)
1307 goto free;
1308
1309 ret = get_comparison_strings(one, two);
1310 free:
1311 free_string(one);
1312 free_string(two);
1313 return ret;
1314 }
1315
1316 int possible_comparison(struct expression *a, int comparison, struct expression *b)
1317 {
1318 char *one = NULL;
1319 char *two = NULL;
1320 int ret = 0;
1321 char buf[256];
1322 struct sm_state *sm;
1323 int saved;
1324
1325 one = chunk_to_var(a);
1326 if (!one)
1327 goto free;
1328 two = chunk_to_var(b);
1329 if (!two)
1330 goto free;
1331
1332
1333 if (strcmp(one, two) == 0 && comparison == SPECIAL_EQUAL) {
1334 ret = 1;
1335 goto free;
1336 }
1337
1338 if (strcmp(one, two) > 0) {
1339 char *tmp = one;
1340
1341 one = two;
1342 two = tmp;
1343 comparison = flip_comparison(comparison);
1344 }
1345
1346 snprintf(buf, sizeof(buf), "%s vs %s", one, two);
1347 sm = get_sm_state(compare_id, buf, NULL);
1348 if (!sm)
1349 goto free;
1350
1351 FOR_EACH_PTR(sm->possible, sm) {
1352 if (!sm->state->data)
1353 continue;
1354 saved = ((struct compare_data *)sm->state->data)->comparison;
1355 if (saved == comparison)
1356 ret = 1;
1357 if (comparison == SPECIAL_EQUAL &&
1358 (saved == SPECIAL_LTE ||
1359 saved == SPECIAL_GTE ||
1360 saved == SPECIAL_UNSIGNED_LTE ||
1361 saved == SPECIAL_UNSIGNED_GTE))
1362 ret = 1;
1363 if (ret == 1)
1364 goto free;
1365 } END_FOR_EACH_PTR(sm);
1366
1367 return ret;
1368 free:
1369 free_string(one);
1370 free_string(two);
1371 return ret;
1372 }
1373
1374 struct state_list *get_all_comparisons(struct expression *expr)
1375 {
1376 struct smatch_state *state;
1377 struct string_list *links;
1378 struct state_list *ret = NULL;
1379 struct sm_state *sm;
1380 char *tmp;
1381
1382 state = get_state_expr(link_id, expr);
1383 if (!state)
1384 return NULL;
1385 links = state->data;
1386
1387 FOR_EACH_PTR(links, tmp) {
1388 sm = get_sm_state(compare_id, tmp, NULL);
1389 if (!sm)
1390 continue;
1391 // FIXME have to compare name with vsl
1392 add_ptr_list(&ret, sm);
1393 } END_FOR_EACH_PTR(tmp);
1394
1395 return ret;
1396 }
1397
1398 struct state_list *get_all_possible_equal_comparisons(struct expression *expr)
1399 {
1400 struct smatch_state *state;
1401 struct string_list *links;
1402 struct state_list *ret = NULL;
1403 struct sm_state *sm;
1404 char *tmp;
1405
1406 state = get_state_expr(link_id, expr);
1407 if (!state)
1408 return NULL;
1409 links = state->data;
1410
1411 FOR_EACH_PTR(links, tmp) {
1412 sm = get_sm_state(compare_id, tmp, NULL);
1413 if (!sm)
1414 continue;
1415 if (!strchr(sm->state->name, '='))
1416 continue;
1417 if (strcmp(sm->state->name, "!=") == 0)
1418 continue;
1419 add_ptr_list(&ret, sm);
1420 } END_FOR_EACH_PTR(tmp);
1421
1422 return ret;
1423 }
1424
1425 static void update_links_from_call(struct expression *left,
1426 int left_compare,
1427 struct expression *right)
1428 {
1429 struct string_list *links;
1430 struct smatch_state *state;
1431 struct compare_data *data;
1432 struct symbol *left_sym, *right_sym;
1433 char *left_var = NULL;
1434 char *right_var = NULL;
1435 struct var_sym_list *left_vsl;
1436 const char *var;
1437 struct var_sym_list *vsl;
1438 int comparison;
1439 char *tmp;
1440
1441 left_var = chunk_to_var_sym(left, &left_sym);
1442 if (!left_var)
1443 goto done;
1444 left_vsl = expr_to_vsl(left);
1445 right_var = chunk_to_var_sym(right, &right_sym);
1446 if (!right_var)
1447 goto done;
1448
1449 state = get_state(link_id, right_var, right_sym);
1450 if (!state)
1451 return;
1452 links = state->data;
1453
1454 FOR_EACH_PTR(links, tmp) {
1455 state = get_state(compare_id, tmp, NULL);
1456 if (!state || !state->data)
1457 continue;
1458 data = state->data;
1459 comparison = data->comparison;
1460 var = data->var2;
1461 vsl = data->vsl2;
1462 if (strcmp(var, right_var) == 0) {
1463 var = data->var1;
1464 vsl = data->vsl1;
1465 comparison = flip_comparison(comparison);
1466 }
1467 comparison = combine_comparisons(left_compare, comparison);
1468 if (!comparison)
1469 continue;
1470 add_comparison_var_sym(left_var, left_vsl, comparison, var, vsl);
1471 } END_FOR_EACH_PTR(tmp);
1472
1473 done:
1474 free_string(right_var);
1475 }
1476
1477 void __add_comparison_info(struct expression *expr, struct expression *call, const char *range)
1478 {
1479 struct expression *arg;
1480 int comparison;
1481 const char *c = range;
1482
1483 if (!str_to_comparison_arg(c, call, &comparison, &arg))
1484 return;
1485 update_links_from_call(expr, comparison, arg);
1486 add_comparison(expr, comparison, arg);
1487 }
1488
1489 static char *range_comparison_to_param_helper(struct expression *expr, char starts_with, int ignore)
1490 {
1491 struct symbol *param;
1492 char *var = NULL;
1493 char buf[256];
1494 char *ret_str = NULL;
1495 int compare;
1496 int i;
1497
1498 var = chunk_to_var(expr);
1499 if (!var)
1500 goto free;
1501
1502 i = -1;
1503 FOR_EACH_PTR(cur_func_sym->ctype.base_type->arguments, param) {
1504 i++;
1505 if (i == ignore)
1506 continue;
1507 if (!param->ident)
1508 continue;
1509 snprintf(buf, sizeof(buf), "%s orig", param->ident->name);
1510 compare = get_comparison_strings(var, buf);
1511 if (!compare)
1512 continue;
1513 if (show_special(compare)[0] != starts_with)
1514 continue;
1515 snprintf(buf, sizeof(buf), "[%s$%d]", show_special(compare), i);
1516 ret_str = alloc_sname(buf);
1517 break;
1518 } END_FOR_EACH_PTR(param);
1519
1520 free:
1521 free_string(var);
1522 return ret_str;
1523 }
1524
1525 char *name_sym_to_param_comparison(const char *name, struct symbol *sym)
1526 {
1527 struct symbol *param;
1528 char buf[256];
1529 int compare;
1530 int i;
1531
1532 i = -1;
1533 FOR_EACH_PTR(cur_func_sym->ctype.base_type->arguments, param) {
1534 i++;
1535 if (!param->ident)
1536 continue;
1537 snprintf(buf, sizeof(buf), "%s orig", param->ident->name);
1538 compare = get_comparison_strings(name, buf);
1539 if (!compare)
1540 continue;
1541 snprintf(buf, sizeof(buf), "[%s$%d]", show_special(compare), i);
1542 return alloc_sname(buf);
1543 } END_FOR_EACH_PTR(param);
1544
1545 return NULL;
1546 }
1547
1548 char *expr_equal_to_param(struct expression *expr, int ignore)
1549 {
1550 return range_comparison_to_param_helper(expr, '=', ignore);
1551 }
1552
1553 char *expr_lte_to_param(struct expression *expr, int ignore)
1554 {
1555 return range_comparison_to_param_helper(expr, '<', ignore);
1556 }
1557
1558 char *expr_param_comparison(struct expression *expr, int ignore)
1559 {
1560 struct symbol *param;
1561 char *var = NULL;
1562 char buf[256];
1563 char *ret_str = NULL;
1564 int compare;
1565 int i;
1566
1567 var = chunk_to_var(expr);
1568 if (!var)
1569 goto free;
1570
1571 i = -1;
1572 FOR_EACH_PTR(cur_func_sym->ctype.base_type->arguments, param) {
1573 i++;
1574 if (i == ignore)
1575 continue;
1576 if (!param->ident)
1577 continue;
1578 snprintf(buf, sizeof(buf), "%s orig", param->ident->name);
1579 compare = get_comparison_strings(var, buf);
1580 if (!compare)
1581 continue;
1582 snprintf(buf, sizeof(buf), "[%s$%d]", show_special(compare), i);
1583 ret_str = alloc_sname(buf);
1584 break;
1585 } END_FOR_EACH_PTR(param);
1586
1587 free:
1588 free_string(var);
1589 return ret_str;
1590 }
1591
1592 static void match_call_info(struct expression *expr)
1593 {
1594 struct expression *arg;
1595 struct smatch_state *state;
1596 struct sm_state *sm;
1597 struct compare_data *data;
1598 int comparison;
1599 struct string_list *links;
1600 char *arg_name;
1601 const char *right_name;
1602 char *link;
1603 char info_buf[256];
1604 int i;
1605
1606 i = -1;
1607 FOR_EACH_PTR(expr->args, arg) {
1608 i++;
1609
1610 state = get_state_expr(link_id, arg);
1611 if (!state)
1612 continue;
1613
1614 links = state->data;
1615 FOR_EACH_PTR(links, link) {
1616 if (strstr(link, " orig"))
1617 continue;
1618 sm = get_sm_state(compare_id, link, NULL);
1619 if (!sm)
1620 continue;
1621 data = sm->state->data;
1622 if (!data || !data->comparison)
1623 continue;
1624 arg_name = expr_to_var(arg);
1625 if (!arg_name)
1626 continue;
1627
1628 if (strcmp(data->var1, arg_name) == 0) {
1629 comparison = data->comparison;
1630 right_name = data->var2;
1631 } else if (strcmp(data->var2, arg_name) == 0) {
1632 comparison = flip_comparison(data->comparison);
1633 right_name = data->var1;
1634 } else {
1635 goto free;
1636 }
1637
1638 snprintf(info_buf, sizeof(info_buf), "%s %s", show_special(comparison), right_name);
1639 sql_insert_caller_info(expr, PARAM_COMPARE, i, "$", info_buf);
1640
1641 free:
1642 free_string(arg_name);
1643 } END_FOR_EACH_PTR(link);
1644 } END_FOR_EACH_PTR(arg);
1645 }
1646
1647 static void free_data(struct symbol *sym)
1648 {
1649 if (__inline_fn)
1650 return;
1651 clear_compare_data_alloc();
1652 }
1653
1654 void register_comparison(int id)
1655 {
1656 compare_id = id;
1657 add_hook(&save_start_states, AFTER_DEF_HOOK);
1658 add_unmatched_state_hook(compare_id, unmatched_comparison);
1659 add_merge_hook(compare_id, &merge_compare_states);
1660 add_hook(&free_data, AFTER_FUNC_HOOK);
1661 add_hook(&match_call_info, FUNCTION_CALL_HOOK);
1662 }
1663
1664 void register_comparison_late(int id)
1665 {
1666 add_hook(&match_assign, ASSIGNMENT_HOOK);
1667 }
1668
1669 void register_comparison_links(int id)
1670 {
1671 link_id = id;
1672 add_merge_hook(link_id, &merge_links);
1673 add_modification_hook_late(link_id, &match_modify);
1674 }
1675
1676 void register_comparison_inc_dec(int id)
1677 {
1678 inc_dec_id = id;
1679 add_modification_hook_late(inc_dec_id, &iter_modify);
1680 }
1681
1682 void register_comparison_inc_dec_links(int id)
1683 {
1684 inc_dec_link_id = id;
1685 set_up_link_functions(inc_dec_id, inc_dec_link_id);
1686 }
1687
1688 static void filter_by_sm(struct sm_state *sm, int op,
1689 struct stree_stack **true_stack,
1690 struct stree_stack **false_stack)
1691 {
1692 struct compare_data *data;
1693 int istrue = 0;
1694 int isfalse = 0;
1695
1696 if (!sm)
1697 return;
1698 data = sm->state->data;
1699 if (!data) {
1700 if (sm->merged) {
1701 filter_by_sm(sm->left, op, true_stack, false_stack);
1702 filter_by_sm(sm->right, op, true_stack, false_stack);
1703 }
1704 return;
1705 }
1706
1707 if (data->comparison &&
1708 data->comparison == filter_comparison(data->comparison, op))
1709 istrue = 1;
1710
1711 if (data->comparison &&
1712 data->comparison == filter_comparison(data->comparison, negate_comparison(op)))
1713 isfalse = 1;
1714
1715 if (istrue)
1716 add_pool(true_stack, sm->pool);
1717 if (isfalse)
1718 add_pool(false_stack, sm->pool);
1719
1720 if (sm->merged) {
1721 filter_by_sm(sm->left, op, true_stack, false_stack);
1722 filter_by_sm(sm->right, op, true_stack, false_stack);
1723 }
1724 }
1725
1726 struct sm_state *comparison_implication_hook(struct expression *expr,
1727 struct stree_stack **true_stack,
1728 struct stree_stack **false_stack)
1729 {
1730 struct sm_state *sm;
1731 char *left, *right;
1732 int op;
1733 static char buf[256];
1734
1735 if (expr->type != EXPR_COMPARE)
1736 return NULL;
1737
1738 op = expr->op;
1739
1740 left = expr_to_var(expr->left);
1741 right = expr_to_var(expr->right);
1742 if (!left || !right) {
1743 free_string(left);
1744 free_string(right);
1745 return NULL;
1746 }
1747
1748 if (strcmp(left, right) > 0) {
1749 char *tmp = left;
1750
1751 left = right;
1752 right = tmp;
1753 op = flip_comparison(op);
1754 }
1755
1756 snprintf(buf, sizeof(buf), "%s vs %s", left, right);
1757 sm = get_sm_state(compare_id, buf, NULL);
1758 if (!sm)
1759 return NULL;
1760 if (!sm->merged)
1761 return NULL;
1762
1763 filter_by_sm(sm, op, true_stack, false_stack);
1764 if (!*true_stack && !*false_stack)
1765 return NULL;
1766
1767 return sm;
1768 }
Static analysis for C